How to Install a Sidewalk Over Old Concrete

Using existing concrete as a base for a new sidewalk saves you valuable time and resources. If the concrete is still in good condition, with no extreme cracks running across, you'll have a strong, durable foundation. Whether you intend to install pavers, clay bricks or natural stones over the concrete, use mortar to adhere the material to the concrete and fill the joints with sand to prevent grime from building in the joints.

Things You'll Need

Hose

Wire scrub brush

Power washer

Concrete stain remover

Putty knife

Vinyl concrete patching compound

Mortar mix

Notched trowel

Board

Cloth

Fine sand

Scrub the concrete with a hose and a wire scrub brush, or use a power washer if necessary. Apply concrete stain remover to remove any grease stains and rinse off the solution.

Patch any small pits and cracks with a putty knife and vinyl concrete patching compound.

Mix mortar from water and pre-made mortar mix. When ready, the mixture should be spreadable like brownie batter.

Add a ½-inch layer of mortar over the first section of concrete with a notched trowel, enough to set about four stones. Set the flagstones in the mortar, leaving as narrow a space as possible between the stones. Put a board across the first section and use equal force over the surface to embed them in the mortar.

Continue to set the flagstones in sections. Take off excess with the trowel, and wipe off drops with a moist cloth. Wait two days for the mortar to harden.

Sprinkle fine sand over the surface and press it between the spaces. Continue adding and pressing sand down until the sand joints are full at the top.